<html>

<body>
	<script>
		var tick = function () {
			if (window.ZXing) {
				ZXing = ZXing();
				testZXing();
			} else {
				setTimeout(tick, 10);
			}
		};
		tick();

		function testZXing() {
			var img = new Image;
			img.src = 'Qr-10.png';
			img.onload = function () {

				var width = Math.floor(this.width),
					height = Math.floor(this.height);

				var canvas = document.createElement('canvas');
				canvas.style.display = 'block';
				canvas.width = width;
				canvas.height = height;
				var ctx = canvas.getContext('2d');
				// ctx.rotate(Math.random()*0.1-0.05);
				ctx.drawImage(this, 0, 0, width, height);
				var imageData = ctx.getImageData(0, 0, width, height);
				var idd = imageData.data;
				document.body.appendChild(canvas);

				var decodeCallback = function (ptr, len, resultIndex, resultCount) {
					var result = new Uint8Array(ZXing.HEAPU8.buffer, ptr, len);
					window.resultString = String.fromCharCode.apply(null, result);
				};
				var decodePtr = ZXing.Runtime.addFunction(decodeCallback);

				var image = ZXing._resize(width, height);

				for (var i = 0, j = 0; i < idd.length; i += 4, j++) {
					ZXing.HEAPU8[image + j] = idd[i];
				}

				var err = ZXing._decode_qr(decodePtr);

				console.log("error code", err);
				console.log("result", window.resultString);

				document.body.appendChild(document.createTextNode(err ? ("error: " + err) : window.resultString));

				for (var k = 0; k < 50; k++) {
					for (var i = 0, j = 0; i < idd.length; i += 4, j++) {
						ZXing.HEAPU8[image + j] = idd[i];
					}
					err = ZXing._decode_qr_multi(decodePtr);
					err = ZXing._decode_qr(decodePtr);
				}

				console.time("decode QR");
				for (var i = 0, j = 0; i < idd.length; i += 4, j++) {
					ZXing.HEAPU8[image + j] = idd[i];
				}
				err = ZXing._decode_qr(decodePtr);
				console.timeEnd("decode QR");

				console.time("decode QR multi");
				for (var i = 0, j = 0; i < idd.length; i += 4, j++) {
					ZXing.HEAPU8[image + j] = idd[i];
				}
				err = ZXing._decode_qr_multi(decodePtr);
				console.timeEnd("decode QR multi");

				console.time("decode any");
				for (var i = 0, j = 0; i < idd.length; i += 4, j++) {
					ZXing.HEAPU8[image + j] = idd[i];
				}
				err = ZXing._decode_any(decodePtr);
				console.timeEnd("decode any");

				console.time("decode multi");
				for (var i = 0, j = 0; i < idd.length; i += 4, j++) {
					ZXing.HEAPU8[image + j] = idd[i];
				}
				err = ZXing._decode_multi(decodePtr);
				console.timeEnd("decode multi");

			};
		};
	</script>
	<script async src="zxing.js"></script>
</body>

</html>